Wireless utility meters have become common in the United States.There are models available for
measuring the use of natural gas, water and electricity for individual
households, though the wireless electrical meters are the most common.The meters offer a variety of benefits,
such as reduced cost of obtaining billing information.Some models also offer improved
blackout detection, monitoring of power quality and load reduction during power
shortages.

Some models transmit nearly continuously, while others transmit a
few times a minute.Some older
models transmit a few times a day or even just once a month.

Concerns and protests have been raised by the
public in the last few years, based on numerous complaints from
customers who claim health effects.There have also been protests from professional societies, such as the
International Commission for Electromagnetic Safety (ICEMS) and the American
Academy of Environmental Medicine (AAEM).

This report takes a look at the actual radio frequency radiation
from four models of wireless electrical meters.

Methodology

The four meters were chosen to be far removed
from other meters and other sources of interference.

The instrument used was a Tenmars TM-195 3-axis RF meter, which
measures the frequency band from 50 MHz to 3500 MHz (3.5 GHz).All wireless electrical meters transmit
within that range (usually around 900 MHz).

As the transmissions are not continuous, it was necessary to
measure the peak value, instead of an average.According to Tenmars, the TM-195 instrument samples
(measures) three times a second.As
the pulsed transmissions from the wireless meters are of short duration
(typically around 1/50th second) it was necessary to measure over
several minutes to make sure at least one burst coincided with the instrument’s
sampling.The measurements were
all 5 minutes or longer, with 5 minutes the common period.

The measurements were taken at varying distances from the front
plate of the wireless utility meter.

Measurements were also taken at different angles from the front
plate, to see if the radiation levels were the same in all directions.

The instrument was placed on a tripod, about 5 ft (1.3 meters)
above the ground, to be level with the meter.

Measurements were not taken of the transients
(“dirty electricity”) put on the household wiring, nor of power frequency (ELF)
fields.

Results

The RF emissions from four electrical utility meters were
measured.The meters were of three
types:

•AMR
“bubble up” meter (Itron/Schlumberger C1SR)

•ERT
“wake up” meter (Elster AB1R)

•AMI
mesh smart meter (Landis+Gyr Focus AXR and RXRS4e)

AMR “bubble up” drive-by meter

An Itron type C1SR meter was measured on a house in rural
Arizona, several miles north of Tucson.The C1SR meter is also available under the Schlumberger brand.

This meter was owned by UniSource, one of the
largest utilities in Arizona.UniSource owns the Tucson Electric Power utility, which operates in the
area.

The C1SR meters can be programmed to communicate in various
ways.This meter is programmed to
transmit wirelessly every 30 seconds.1A utility vehicle passes through
the area about once a month to pick up the signals from the meters with a
wireless receiver.The
communication is one-way, the meters do not know when
their signals are needed, so they transmit all the time.

In some areas around Tucson, the utility uses the same meters in
a fixed network where the signals are received by collector units mounted on lamp posts.

The radiation from this C1SR meter was measured at increasing
distances from the front plate, as shown in Table 1.

Table 1:C1SR meter
frontal radiation

Distance
ft m

Radiation
mW/m2

10.3

36.0

31

7.5

51.6

1.7

103.2

0.70

154.8

0.49

206.5

0.24

Ambient

0.06

The radiation from the meter drops off with distance, but was
still above ambient levels at twenty foot distance.

Measurements were also taken behind the meter, which was mounted
on the wall of the house.This
meant that the radiation had to pass through the steel breaker panel and the 12 inch (300 mm) thick wall.The wall appeared to be standard wood-framing,
thus providing little attenuation.At 3 ft (1 meter) from the backside of the meter, the radiation level
was measured to 8 mW/m2.This is a 60 dB reduction from the
same distance from the front side.

ERT “wake up” meter

An Elster AB1R meter was measured in a remote area of
southeastern Arizona.The nearest
town is Rodeo, New Mexico.

The meter is electromechanical with analog dials.Only a close inspection revealed that
it was a wireless ERT meter, which the homeowner was unaware of.The meter has electronics mounted on
the bottom of the mechanical meter, which can only be seen from
underneath.A label indicates the
ERT technology, and also lists an FCC notice.

ERT stands for Electronic Receiver Transmitter.These types of meters are read by a
passing utility vehicle, which has a transmitter that sends out a signal.When the ERT meter receives this
signal, it transmits its data.Otherwise, it does not transmit.

To verify that the meter was not transmitting, the RF instrument
was placed 3 ft from the front plate.The peak value was measured to 0.0137 mW/m2 over
12 minutes.

The ambient level was comparable (0.0099 mW/m2).

AMI mesh smart meters

Mesh smart meters are a part of a sophisticated wireless
network.The meters constantly
communicate with each other to detect if any of the meters are malfunctioning
and to pass along messages in a relay fashion.The network is controlled by special collector units, which
gather up the information from all the meters in the area and pass it on to the
utility.

Mesh networks are very busy.Court-ordered disclosures reveal that for one brand of mesh
network, each meter transmits an average of about 10,000 times a day, with some
meters transmitting as much as 190,000 times a day2.

Two different models of mesh smart meters were measured in the
Dallas, Texas area.Both were of
the Landis+Gyr brand, and using that company’s Gridstream mesh technology,
according to the labels on the meters.

The first meter was located in a park in Hickory Creek, on the
northwest side of the Dallas metro area.A wireless collector unit was found on a lamp post,
about half a mile from the smart meter.

The meter was a Focus AXR model, which is identical to the Focus
AXR-SD, but without a built-in disconnect switch.

The measurements were performed on two consecutive days (April 30
and May 1, 2012).The
results are shown in Table 2.

Table 2:Hickory Creek
Focus AXR mesh, frontal radiation

Distance

Day 1

Day 2

Ft

m

mW/m2

mW/m2

3

1

191

—

5

1.6

116

—

10

3.2

34

22

15

4.8

8

—

20

6.5

4

3

30

9.7

3

2

50

16.1

1

1

100

37.3

0.4

0.4

Ambient

0.6

0.02

All values are peak.

The measurements were taken in the early evening on both days and
are consistent.The radiation
levels reach the ambient levels at a distance of about 100 ft
(32 meters) from the front of the meters.

The ambient levels varied significantly over time.On Day 1, the ambient level was
apparently lower when the 100 ft measurement was performed, than when the
official ambient level was measured.On Day 2, the level was measured to be 30 times lower.This may be due to the varying traffic
on the cell towers in the area.

The radiation levels were measured at various angles relative to
the front, to see how directional the transmitter is.The measurements were taken 10 ft (3 m) from the meter,
as shown in Table 3.

Table 3:Hickory Creek
Focus AXR mesh, angular measurements

Angle

Peak
radiation (mW/m2)

0ľ(front)

26

45ľ

9

90ľ(side)

0.06

180ľ(back)

0.07

Ambient

0.02

The antenna is clearly directional, with the radiation falling
off rapidly to the side and back.At a 90 degree angle and beyond, the level is
reduced by about 50 decibels.

The meter was mounted on a steel box, which could provide
shielding towards the back, but not the side, which was glass.

A Landis+Gyr RXRS4e mesh smart meter
was measured in a rural area near Seagoville, on the southeast side of the
Dallas metro area.This model
meter can be configured with various communication technologies, such as
telephone modem, power line carrier (PLC) and wireless.According to the label, it used
Gridstream Mesh wireless.

A collector unit was found on a lamp post
about a mile away.It is possible
that another unit was closer, but not found.

Measurements were taken from the front and side of the RXRS4e
meter, as shown in Table 4.

Table 4:Seagoville RXRS4e
mesh

Distance

Angle

Peak radiation

ft

m

mW/m2

10

3.2

Front

5.1

30

9.7

Front

0.8

10

3.2

Side
(90ľ)

2.2

Ambient

—

0.2

All values are peak.

The radiation levels on the RXRS4e mesh meter were somewhat lower
than the AXR meter at Hickory Creek.The reduction towards the side was also less (only about 50%).

It was not feasible to measure the radiation level from the back
of this meter.

Discussion and conclusion

Three different wireless technologies are
represented by four different models of meters.

As the meters do not transmit as a continuous wave, the peak
values were collected.Readings
were taken at varying distances to ensure that the values were true and not
affected by the ambient levels.

The peak radiation levels were recorded for periods of at least 5
minutes, and no more than 12 minutes.

These peak levels varied between the models, with the C1SR being
the lowest at 0.7 mW/m2 and the Focus AXR the highest with 34 mW/m2
at 10 ft (3 meters) distance.The
C1SR may transmit less powerfully as its signal is received from a passing
utility vehicle and there is no need for reaching much of a distance.

The C1SR meter transmits every 30 seconds, while the more
powerful mesh meters transmit more often than that, sometimes multiple times a
second.The peak recordings in
this study only determined the strength of each pulse and are not affected by
how frequently the meters transmit.The exposures from the mesh meters may thus be much greater, but cannot
be quantified from this data.

All measurements were taken in rural or semi-rural areas, to
limit interference from other transmitters.That the readings were higher than the ambient levels, and
that they tapered off with increasing distance, indicates that there was no
interference.The readings are
thus credible.

It is possible that wireless meters deployed in more densely
populated areas radiate less powerfully, though with meters placed closer
together, the overall effect may be higher.This would especially be the case with apartment buildings
and strip malls, where several meters may be mounted close together.

This study reveals that the meters do not radiate uniformly in
all directions.The three meters
tested radiated most powerfully out the front.In one case, a person standing 10 ft (3 m) from the side of
the meter would receive a lower dose than someone standing 50 ft (16 m) from
the front.

The ERT meter was found to not radiate any radio frequency when
it was not prompted to do so.This
type of meter is typically read monthly, but does not offer any of the
functionalities needed for the smart grid.It is solely a labor-saving device
and largely considered obsolete.

The ambient peak RF levels measured ranged from 0.0099 mW/m2
in a remote part of Arizona to 0.6 mW/m2 in a park on the outskirts
of the Dallas metro area.A single
wireless smart meter can raise the radiation level above the ambient for a
distance of 50 feet (16 m).

July 2012

End notes

1)Disclosed by
UniSource representatives at the Arizona Corporation Commission hearing about
smart meters on September 8, 2011.Docket E-00000C-11-0328, www.azcc.gov.

2)Disclosed by
Pacific Gas and Electric (PG&E) in response to administrative law judge
ruling.Filed in document titled Pacific Gas and Electric Company’s Response
to Administrative Law Judge’s October 18, 2011 Ruling Directing it to file
Clarifying Radio Frequency Information, November 1, 2011.The document is filed at the California
Public Utilities Commission under Application 11-03-014.